Every aspect of the preservation process, and every treatment,
entails varying degrees of intervention. In fact, each treatment
from "housekeeping" through new construction"
is listed in order of the increasing degree of intervention
imposed on each treatment to the physical fabric. It is a quantitative
listing, not qualitative, and does not presume that on treatment
is "better" or "worse" (more or less "appropriate").
The qualifications for the appropriateness any treatment are
constructed around a policy of "minimum intervention to
the historic fabric" and based on criteria considered through
the preservation process.
As an example, new construction might impose less intervention
to the collection than, say, adaptive use as physical
changes to the interior of a historic structure may have a greater,
negative impact on the fabric than an addition to the exterior.
"Minimum intervention and reversibility are stated as
being the two basic principles that lie behind all conservation
"Preventive conservation is the ongoing activity of non-invasive
actions taken to prevent damage to and minimize deterioration
of museum objects."
Inskip, P and Cannell, D, Problems tn the Renewal of Services
in Historic Buildings, Module 7, RICS Diploma in Building
Conservation, The College of Estate Management, UK, 1991as
cited in Bridger, Colin and Nichols, Justine. An Investigation
into the Refurbishment Characteristics Encountered When Integrating
Modern Building Services into Historic Buildings. Oxford
Brookes University, Oxford. [Download as PDF format file.]
" Minimum intervention aims to preserve as much
original material as possible, doing no more than is strictly
necessary to guarantee the proper use, conservation and prolongation
of the life of the original fabric. Its aim is to
protect the original elements not just appearance, by applying
a proportionate response to any intervention.
"Reversibility originated in the field of paintings
conservation, where it is still a major criterion in selecting
of appropriate treatment. In buildings conservation reversibility
is harder to achieve and in the conservation of archaeological
sites, reversibility is harder still to gauge. Reversibility
has more recently been replaced by principles of compatibility
and retreatability: a more sustainable conservation strategy,
at the same time, stressing the importance of maintenance regime.
"Compatibility requires that treatment materials do not
have negative consequences, and retreatability requires that
the present conservation treatment will not preclude or impede
future treatments. These principles are more sustainable because
they are more realistic and enable future treatments to take
advantage of progress in scientific knowledge. Maintenance is
implied: in other words it is acknowledged that the next treatment
is not likely to be the last.
"These principles provide a framework for deciding on
acceptable and unacceptable conservation interventions. Yet
these principles are not static: they have evolved with time,
partly as a consequence of the internal development of conservation
as a profession, and partly in response to changes in the human
perception of the world and in particular of the environment."
and Training Needs for the Conservation and Protection of
Cultural Heritage: is it a case of 'one size fits all'?,
Workshop 2 Key Note Presentation by May Cassar, Director of
the Centre for Sustainable Heritage, University
College London, Cultural Heritage Research: a pan-European
Challenge, Cracow, 16-18 May 2002.
"The appropriate level of intervention can only be chosen
after careful consideration of the merits of the following:
- cultural significance,
- condition and integrity of the fabric
- contextual value
- appropriate use of available physical, social and economic
B. Framework, Appleton
Charter for the Protection and Enhancement of the Built
Canada, August 1983.
"Interpretation has to be based on authentic qualities
of the object. And if we want to pass down the objects to posterity
as true documents, we have to care very much for the original
substance. The extent to which this is spared during particular
operations in conservation will depend very much on interpretation,
mostly that by the conservator."
Jedrzejewska, Hanna. Ethics in Conservation, Stockholm,
"Measures will be undertaken to prevent or reduce deterioration
of original....[material]... by attempting to control the causes,
without physical or chemical intervention. Only when certain
criteria have been met, such as intrinsic value or cost effectiveness,
will action be undertaken to treat and/or restore these records."
ANLA Preservation Policies And Procedures Manual For Small
Archives, Association of
Newfoundland and Labrador Archives, 2000.
"Certain items in a collection are so significant that
they warrant conservation attention. Conservation of such items
is especially appropriate when the materials cannot withstand
use even careful use without being damaged, when
they are physically or chemically unstable, or when they have
received inappropriate treatment in the past."
Paris, Jan. Choosing
and Working with a Conservator, Technical Leaflet, Conservation
Procedures, Section 6, Leaflet 9, North
East Document Conservation Center, 1999.